The present invention relates to replaceable ink supply containers for providing ink to printers. More specifically, the present invention relates to ink containers having both a fluid outlet and a plurality of electrical contacts which must make a highly reliable fluid and electrical interconnect with a printing system.
Inkjet printers frequently make use of an ink-jet printhead mounted to a carriage which is moved back and fourth across a print media, such as paper. As the printhead is moved across the print media, a control system activates the printhead to eject, or jet, ink droplets onto the print media to form images and characters.
Previously, printers have made use of an ink container that is separably replaceable from the printhead. When the ink cartridge is exhausted the ink cartridge is removed and replaced with a new ink container. The use of ink containers allows the user to separately replace the ink container without replacing the printhead, thereby allowing printing until the end of printhead life.
As a benefit to the user of the printer information is sometimes stored on these ink containers to maximize the quality of the output image as well as improve the printers ease of use. For example, U.S. Pat. No. 5,506,611 to Ujita et al discloses the use of an ink container having a memory device located thereon for storing printer parameters. More specifically, the Ujita reference discloses the use of storing printhead drive conditions in the memory on the ink container. Once the ink container is inserted into the printer these drive conditions are read by the printer to determine optimum printhead drive conditions for the particular ink associated with the ink container. These drive conditions include drive voltage, pulse width, frequency, and the number of preliminary discharges. In this manner, the printer is optimized for printing the particular ink without requiring the user to manually adjust these drive conditions.
One problem associated with the use of electric terminals for transferring information between the ink container and the printer as discussed in Ujita is that electric terminals are subject to contamination. Once the electric terminals are contaminated, the electrical connection between the ink container and the printer may be unreliable. One source of contamination for these electric terminals is the ink contained within the ink container. As the ink container is inserted into the printer the ink container makes a fluid interconnect with the printer. As the ink containers are swapped in and out for different applications, ink from the ink containers can spill or splatter. If this ink finds its way to the electric terminals on the ink container the reliability of the electrical interconnect between the ink cartridge and the printer may be reduced. Once the electrical interconnect between the ink cartridge and the printer fails or is shorted by fluid such as ink, then the quality of the output image may be reduced.
Another source of contamination for the electric terminals on the ink container results from the handling of the ink container. The ink container must be handled to insert the ink container into the printing system. In addition, the ink containers may be swapped in and out depending on the particular application. Some applications require printing on specific media. In this case, the ink must be changed to an ink that is optimized for the particular media chosen. The handling of the ink cartridges can transfer oils and salts frequently present in human skin to the electric terminals on the ink container reducing the reliability of the electrical interconnect between the ink container and the printer. In addition, once the ink container electric terminals are contaminated, this contamination may be transferred to the electric terminals on the printer further reducing the reliability of the electrical interconnect between not only the contaminated ink container, but all subsequent ink containers which are inserted into the printer.
There is an ever present need for ink-jet printing systems which are highly reliable and are capable of providing high quality output images with minimal intervention by the user. These printing systems should be cost effective and have relatively low operating costs. In addition, the ink container should have some form of storage device which contains essential printer parameters which must be changed or compensated for to accommodate the particular ink stored within the ink container. This ink container should contain any additional parameters such as ink supply volume information or drop count information to provide additional benefits. These benefits include low ink warnings to minimize the need for the user to monitor this parameter. For the case where replaceable ink supplies are used, the ink container should be easily inserted into the printer. The ink container should be capable of making reliable fluid connection with the printer without spilling or splattering during insertion and removal. In the event that spilling or leakage of ink occurs, this spilled ink should not contaminate the electrical contacts which can lead to system reliability problems.
The ink container should be capable of making a highly reliable electrical interconnect with the printer for transferring information between the storage device and the printer. This electrical interconnect should be capable of repeated uses without loss of reliability.